Nikola Tesla -
Inventing a Legend
Higher and higher
By the time the first polyphase AC system had gone on public demonstration (at the Chicago Worlds’ Fair in 1893) Tesla had long moved his interest to the higher alternating frequencies. Using tuned circuits (inductive coils in series/parallel with capacitors) which to date had only been a scientific curiosity discovered in 1856 by Sir William Thompson (Lord Kelvin), Tesla announced the heating effect of high frequencies on the human body and in an AIEE lecture recommended the effect for medical treatment. He had effectively discovered diathermy but he made no effort to pursue it, his air-cored transformers (Tesla coils) were far more useful for high voltage generation and he began to investigate high frequency discharge processes.
The Celebrated Tesla
Invitations to lecture came in from all the great nations and for a while Tesla was busy in London and Paris revelling in his self-absorbing but breathtaking 3 hour lectures. In London Sir James Dewar prevailed on a reluctant Tesla to give a lecture at the Royal Institution by sitting him in Faraday's chair and sacrificing a generous tote from Faraday's own whisky bottle - supposedly not opened for 35 years. Had Tesla known Faraday's religious background he may well have disputed the authenticity of the amber liquid.
In 1886 the Cataract Construction Company opened a $3000 first prize contest for the best way to harness the huge outflow from the Niagara Falls. With Buffalo and its industries only 22 miles distant, it was believed that the 7,000,000 horsepower from the falls would easily supply not only Buffalo, but possibly New York, with all necessary electricity.
George Westinghouse, however, thought that the organisers were trying to get an engineering solution for practically nothing and refused to get involved. He was also aware that the CCP had engaged Lord Kelvin as its technical advisor and that Kelvin, incongruously since he had investigated AC systems and discovered the inductive/capacitive tuned circuit, had no faith in ideas about AC transmission.
Yet a direct current system to Buffalo was entirely untenable even at higher generator voltages due to the still huge copper (cable) costs. By 1890 both the (Edison) General Electric Company and the Westinghouse Company had been invited to tender for the project - GE proposing a three phase AC system and Westinghouse a two phase AC system. To Westinghouse's delight GE (Edison's old company) were forced to license the Tesla system from Westinghouse.
The Parsons/Tesla Hydroelectric Power system at Niagara Falls came on line first in August 1895 to supply the Pittsburgh Reduction Company to make possible the Hall electrolytic process for Aluminium. Power to Buffalo was inaugurated a year later in 1896.
Tesla, however delighted he might have been, had little opportunity to enjoy his fame. He was now embroiled in claim and counter-claim over priority and precedence in AC systems. A problem which was very hurtful to him because legally it was Westinghouse's responsibility, they now owned the patents, but it was Tesla that risked the reputation. Fortunately the matter was fairly quickly resolved as court judgment followed court judgment in Tesla's favour.
Tesla was now at work on his 'world wide system' a radio transmission method based on the now famous Tesla coil derived in part from the ubiquitous Kelvin tuned circuit. Generating AC currents, the tuned circuits were also capable of detecting radiation from signal sources having frequencies equal to the resonant frequency of the tuned circuits. Tesla was detecting signals at some distance and was ready to demonstrate a long distance wireless communication system. He intended to take his receiving apparatus up the Hudson River in the spring for a convincing demonstration of his apparatus. Apart from simply generating a radio signal he was testing the range that his low power system could achieve. He was already aware that a long range system was going to need a far more powerful transmission system and for this he was going to need a method to discharge more power. Spark generation had been shown to be a powerful source of electro-magnetic radiation - Tesla could usefully convert the earlier induction coil work by H.D. Ruhnkorff (Rumkoff) of 1860, and by Spottiswoode and Apps (1877), to his advantage. Using De La Rive trembler systems these workers had demonstrated large inductive spark discharge systems employing massive inductors (and auto-transformers). However, Tesla understood one important phenomenon - that of coil self-resonance where the interwinding capacitance created a tuned circuit with the winding inductance. This was the source of the voltage (power) magnification he was later to use to great effect.
But tragedy struck on the 13th of March 1895 when fire broke out in the South Fifth Street building in which Tesla's laboratory was housed. Everything was lost including all that he had ever constructed or recorded - his whole life had been contained within the laboratory. Rumours circulated that it was an 'Edison fire' but the indictment was never substantiated.
The lab remained the property of the Tesla Electric Company, owned by Tesla and A.K. Brown. Most of the Westinghouse $1,000,000 had gone into the company or to its associates. With no insurance cover the company was essentially wiped out. Tesla himself had some free money, enough for his living expenses, but no more.
Edward Dean Adams, head of the Niagara project and senior director of the Morgan Financial Group, immediately offered Tesla $100,000 to start a new company and offered the combined support of himself and the Morgan group. However, John Pierpoint Morgan was the financial force behind the (Edison) General Electric Company and had backed many big Edison projects. Likewise, Morgan had backed the Tesla Niagara project, but this was no consolation to Tesla. He rejected any involvement with Edison and, ergo, with Morgan. He chose to limp on with a mere $40,000 subscribed personally by Adams. It took a year of hard work and support from associates for Tesla to rebuild his laboratory, but once done he soon caught up.
In 1889 high voltage, high frequency experiments came to a zenith, particularly in high vacuum Crookes and Geissler tubes. Different gases ionised readily in high frequency fields and Tesla experimented with low pressure gas filled tubes containing zinc sulphide and other phosphorescent and fluorescent materials. They glowed in the ionised gases as electrons or ultra-violet rays excited them. Thus were demonstrated the first fluorescent lighting tubes.
In 1891, he used radio frequencies to bring a carbon or Carborundum button to incandescence within a rarefied globe. So intense was the effect that the carbon button lamp was 20 times as bright as its incandescent equivalent for the same amount of power input. Tesla could produce extremely high temperatures in the globes - carbon could be vaporised instantly - and in some instances, where the frequency was right, the residual gases would glow from being electro-magnetically ionised (plasma). At certain frequencies and gas pressures, and with globes of a certain size, a radiation would be produced of an intense and monochromatic nature. The effect was suspiciously like that of a laser.
Similarly, Tesla was able to produce a forerunner of the point electron microscope - by creating a hard vacuum in his globes and through careful control of the applied potential he could visualise the microscopic surface of his button electrodes as they emitted high energy electrons characteristic in density of the micro-surface topography. The globe surface resolved this better if covered in phosphorescent materials. This was almost a cathode ray tube.
Invention and Fame
Edison had attempted to undermine AC as more dangerous than DC but Tesla would prove his point in lectures by holding his fluorescent and incandescent lamps at arms length and passing the high frequency currents through his body. Gasps of amazement came from audiences as, with no apparent connection to anything, the lamps would suddenly come to life and illuminate the lecture theatre.
But this to Tesla was a mere party trick, he had other priorities, made clear by his showing of a radio controlled boat in September 1898 at Madison Square Garden. The demonstration was so flawless as to be thought simple, few understood its massive implications - not only was the boat 'radio' controlled but it was full of entirely original technology.
This public experiment was to herald the great Tesla coil radio system at Colorado Springs. Tesla had now developed a 4,000,000 volt DC to AC tuned oscillator - but he wanted to go higher and this required more space. The $40,000 from Adams and other generous benefactors had run out, so too had Tesla's meagre reserves. But friends came to the rescue and Tesla had one singular piece of luck. Leonard Curtis, manager of the Colorado Springs Electric Company and an admirer of Tesla, invited him to locate his laboratory near the power station. Then a Tesla disciple, Col J.J. Astor, offered $30,000 to amortise costs. Things were going well, Curtis told Tesla he could have all the land he could use and 'all the power necessary'. But this latter was to prove prophetically absurd.
The experimental station at Colorado Springs was a huge wooden shed topped with a 60 ft pylon like structure truncated at the top and carrying a three foot copper ball on the end of a 200 foot mast. Close by was a second pylon acting as the return conductor. Inside, Tesla had his control rooms, switching banks and coils all feeding the gigantic Tesla tuned circuits connected to the mast. The series of high voltage experiments covered the period 1899 to 1900 during which Tesla proved that the earth was a conductor. The very first artificial lightning experiment was spectacular but lasted less than a minute. In this short time Tesla, outside the lab block, saw 135 foot discharges generated from the mast ball (a discharge potential of some 168,000,000 volts). The inside of the laboratory was reported to be sizzling and emitting a blue haze prior to the experiment being suddenly terminated. The power station generator had overloaded and caught fire necessitating the use of the standby generator. The burnt out dynamo was one which Tesla had originally designed, so he was obliged to repair it (which he did within a week) because Curtis had switched Tesla's experiment off the domestic grid.
Later, using a 150,000 Hz self-tuned oscillator, Tesla discharged massive potentials into the earth and subsequently slowly created an earth 'resonance'. He could detect his signals over a 26 mile radius from his station - specifically by lighting over 200 unwired Tesla fluorescent lamps. He expected to be able to circle the earth with a resonant field. In short, he had developed a spark discharge continuous wave transmission system, using ground wave 'earth resonance' as a method of communicating around the globe. More importantly, he had demonstrated the wire-free transmission of electrical power.
Publishing an article in Century Magazine Tesla again caught the interest of J.P. Morgan whom he had turned away from previously. This time however Morgan made a personal appeal to Tesla to discuss the future of Tesla's experimental work. Tesla relented and was soon a frequent visitor to Morgan's home (Tesla later thanked Morgan for his support in a 1904 article but this was very much post-event and Morgan had by this time withdrawn his support from Tesla's research). While Morgan was involved it gave Tesla some valuable credibility. By 1900 Tesla had been lent $150,000, enough for the final test of his world system.
Tesla was invited to build a new transmitter station and laboratory on a 2000 acre site at Shoreham (in Suffolk County, Long Island) by James Warden, who gave the site the name of Wardenclyffe. Enormous difficulties were faced in the design of the new self-standing 154 foot pylon with 100ft mast, nothing like it had been accomplished before. Time passed, and though Tesla carried out much in his completed laboratory complex, work on the transmitter was never finished. Tesla changed the design specification and ran out of money and credibility too soon. Rumours had strengthened on the basis that J.P. Morgan had withdrawn his support and although Morgan continued to make personal contributions to Tesla's living expenses his absence from the pool of supporters for the experimental work broke confidence in Tesla's scheme and the money from other financial sources dried up.
The Final Burst
Tesla retired to offices at 165 Broadway New York and continued in the role of inventor extraordinary. He had long had an idea (1902) for a very efficient steam turbine - his experimental model was amazing. Using 12 closely spaced 5 inch discs on a single shaft Tesla used first compressed air and then steam to produce a rotational velocity of some 35,000 rpm. The external clearance was crucial and was reduced to almost touching tolerances as the discs stretched under the enormous centrifugal force. It is notable that the turbines were not bladed but depended on surface friction between the driving fluid and the disc surface. A later, nine disc, system running at 11000 rpm produced almost 110 horsepower - approximately 20 horsepower per pound weight. Efficient and elegant though the idea was Tesla could find no takers - at this time Westinghouse were developing the Parson's turbine and General Electric were concentrating on the Curtis turbine. In 1925 The Allis Chalmers Company did however take up the challenge but a full scale test of the Tesla system proved unsatisfactory - a 500 KW turbine was no better than 38% efficient. Only at higher rotational speeds could the efficiency be increased but at 12000 rpm the turbine was not expected to be durable. Tesla abandoned the project when he was unable to secure a test using his turbines in sequence, as a compound unit taking the exhaust steam from the first to lead to a second and so on.
The Man and his Honours
Tesla's final period, covering the years 1905, when the Wardenclyffe project was abandoned, and 1943 when he died, were more to do with Tesla the icon than Tesla the brilliant experimentalist and engineer. His offices in New York became a Mecca for inventive pilgrims and admirers, Tesla himself unfolded into the mysterious habits he had always been prone to but had never been too obvious when he was immersed in his projects. Much of his developing eccentricity has been attributed to the death of his mother in 1892
His life became a paradox, a strict protocol and regimen from which he would periodically deviate. His personal culture was fussy, and nearly always that which he perceived to be the habits of a gentleman - he was tall elegant and carried himself proudly. His dress was always immaculate. His clothes were regulated, he wore tailored suits, high button hand-made shoes and his ties were either black or red striped. Even his dove grey gloves were unfailingly replaced at the same time each week at $1 per pair.
Tesla lived a seemingly lonely and aloof existence - he was principled and unyielding. He never appeared to court women and apparently had no sexual involvement at all though he always employed young attractive secretaries who were heavily governed by Tesla in their attire. He had a definite dress code for his female employees and insisted on things being de mode. Tesla was proud of what he had become. He expected respect, expected service, but was always generous in return when his aloof dignity and massive personal vanity was fostered. He was intellectually gifted, superbly knowledgeable and the keeper of an ideal. Yet he was not averse to being seen drinking in the notorious New York Bowery or attending rowdy burlesque shows.
He never moved from hotels because he expected exemplary hotel service (as it was then) as a minimum, and wanted no part of a domestic existence. He avoided the things which offended him, and there were many. His foibles and anathemas' were great, he could not eat at a dinner party if a female guest was wearing pearls and, except for formal requests, he would always eat alone, served only by the head waiter, refusing offers to join him and only holding dinner parties himself when it suited. His friends and acquaintances generally saw him at luncheon. Conversely, he allowed wild pigeons, particularly one female for whom he had a marked and somewhat unhealthy predilection, to live in his apartments. Twice hotels insisted he either refrain from feeding his pigeons or move - Tesla moved. Yet, for all this, Tesla was thought to be a charming and fulfilling associate and his clipped, perfectly pronounced and almost archaic speaking 'made you want to listen'. He was a bad business man who was intelligent enough to realise that in this respect he was his own worst enemy. He hired a business manager, but then neglected his advice.
In 1912 Tesla refused to share the Nobel Prize in physics with Edison - even though he was desperately in need of the $20,000 dollars it would have brought. He was offended at having the Nobel committee treat him and Edison on equal terms but was even more resentful of Marconi who had received the Nobel accolade three years earlier; Tesla honestly believed he had precedence over Marconi in radio communication, though unlike Marconi, Tesla appears never to have modulated his radio signals with telegraphy or speech and undoubtedly Oliver Lodge would have contended Tesla's claims regarding the tuned circuit. Tesla's dispute with the Nobel committee was damaging, in the end they disavowed both Tesla and Edison and offered the prize to the Swedish engineer/scientist Nils Gustav Dalen. It was awarded to Dalen for his light sensitive gas valve used in unmanned lighthouses etc, and for work on acetylene, but more importantly for his investigations into the safe use of explosive gas mixtures. (An unkindly omen, it was said, for a laboratory explosion blinded Dalen in the same year he became the Nobel laureate. Though sightless he later invented the AGA cooker in 1924).
Curiously, in 1917, Tesla grudgingly condescended to accept the Edison Medal from the American Institute of Electrical Engineers, but not without some indifference - just prior to the award ceremony he was found to be missing. He was discovered in New York's Plaza Library festooned with pigeons who had come to eat the bird-seed that Tesla always bought for them. Later, short of money, Tesla pawned the solid gold Edison Medal to pay his secretaries and to buy bird seed.
Contrary to his lifelong meticulousness in his engineering, Tesla seldom recorded anything in writing (though he occasionally kept a diary). He could depend on an almost perfect recall and it appears that he rarely made technical notes unless it was for a lecture or a publication. It is true that most of his earlier technical records were lost when the first New York laboratory burnt down, but little of his later work survives either. Most of his lecture notes survive, he wrote articles, preliminary patent specifications (he is credited with 116 patents in 9 different categories), had a wealth of personal correspondence and gave many interviews, but of his engineering notes little is now extant. This has resulted in there being much to challenge about what Tesla actually accomplished, though few in his circle of contemporaries, nor his adherents today, harboured any doubts. Even his thoughts on a Death Ray, much publicised in 1933, never received a comprehensive description.
Tesla once said that he expected to live to be at least 100 and that he would complete an auto-biography in good time. In the event, and by his own standards, he died prematurely (and alone) in his New Yorker Hotel room on the night of Thursday the 7th of January 1943. Within hours the FBI had seized what few papers were in Tesla's safe in the interests of national security.
Those in Tesla's select band of admirers mourned his passing but comparatively few in the year of his death recognised his name in the obituaries. The Tesla Superman was dead and had been for many decades so the majority of the public thought. Engineers, on the other hand would never forget, nor would many scientists.
Three months after Tesla died the US Supreme Court overturned the Marconi patents in radio and awarded precedence to Tesla though this had little effect in correcting the popular view of Tesla's place in originating radio. Later, In 1954 it was proposed and approved by the International Electrical Commission that the unit of magnetic flux density (or magnetic induction, equivalent to 1 weber m-2) be given the term Tesla. This was also approved and instituted by the International Union of Applied Physics in 1961. An honour Tesla would have appreciated given that neither Edison nor Marconi were even mentioned.
A spectacular demonstration - Tesla Appears to sit reading impassively under a massive electrical discharge at the Colorado Springs Station but this was contrived for publicity purposes by using a double-exposure technique.
Chicago Worlds' Fair, 1893
Sir William Thomson - Lord Kelvin
Sir James Dewar
Tesla AC Generators at Niagara Falls
Tesla Coil Discharge
Interior of the Fifth Street Workshop, NY
Edward Dean Adams
J P Morgan
Wireless Flourescent Tube lit by a Tesla Coil
Tesla's Radio-Controlled Boat
Colorado Springs Station
Tesla Tower, Wardenclyffe
Tesla Steam Turbine
Nikola Tesla - Formal Portraits
Tesla celebrates his 75th Birthday at the New Yorker Hotel
Tesla shortly before his death, aged 87
Memorial Plaque - New Yorker Hotel